diff --git a/ClosedXML/Excel/XLWorkbook_Load.cs b/ClosedXML/Excel/XLWorkbook_Load.cs
index 6df9e8e..c515d2d 100644
--- a/ClosedXML/Excel/XLWorkbook_Load.cs
+++ b/ClosedXML/Excel/XLWorkbook_Load.cs
@@ -1721,12 +1721,16 @@
                     {
                         if (openXMLFill.PatternFill.BackgroundColor != null)
                             closedXMLFill.BackgroundColor = GetColor(openXMLFill.PatternFill.BackgroundColor);
+                        else
+                            closedXMLFill.BackgroundColor = XLColor.FromIndex(64);
                     }
                     else
                     {
                         // yes, source is foreground!
                         if (openXMLFill.PatternFill.ForegroundColor != null)
                             closedXMLFill.BackgroundColor = GetColor(openXMLFill.PatternFill.ForegroundColor);
+                        else
+                            closedXMLFill.BackgroundColor = XLColor.FromIndex(64);
                     }
                     break;
 
@@ -1736,6 +1740,8 @@
 
                     if (openXMLFill.PatternFill.BackgroundColor != null)
                         closedXMLFill.BackgroundColor = GetColor(openXMLFill.PatternFill.BackgroundColor);
+                    else
+                        closedXMLFill.BackgroundColor = XLColor.FromIndex(64);
                     break;
             }
         }
diff --git a/ClosedXML_Tests/Resource/Other/StyleReferenceFiles/TransparentBackgroundFill/TransparentBackgroundFill.xlsx b/ClosedXML_Tests/Resource/Other/StyleReferenceFiles/TransparentBackgroundFill/TransparentBackgroundFill.xlsx
index 6953f33..8d63ec0 100644
--- a/ClosedXML_Tests/Resource/Other/StyleReferenceFiles/TransparentBackgroundFill/TransparentBackgroundFill.xlsx
+++ b/ClosedXML_Tests/Resource/Other/StyleReferenceFiles/TransparentBackgroundFill/TransparentBackgroundFill.xlsx
Binary files differ